Safety gate for projectiles



y.13111.4, 1949. i l W, J, FLETT 2,458,468

SAFETY GATE FOR PROJECTILES Filed Jan. 26, 1943 Ff. g

' 24 f F165 l F/aa INVENTOR W/LL/AM J. FLETT BY A /3 .24 I8, A ORNEY -for releasing the gate.

Patented Jan. 4, 1949 jorf1=11fet serait represented-by the Secretaryfof the Navy Application January 26, IS,`

1 claim. (o1. ro-2mb) This invention relates to safetyfdevicesfor ex'- plosive projectiles vof'ther rotarytypex: and has particulari'eiern'e t'a 'nox'rel safety device for preventing premature explosion of the projectile through thering train and 'which remains in annarm'd or safe position 'until it has lbeen afcteii iip'on by the dual v`forces "of setback and centrifugal force incident to firing the projectile from a gun.

One object of the invention is to provide a novel safety gate in the firing train of a projectile fuze, in which the gate element is normally locked in its safe or unarmed position until the device is acted upon successively by a force of setback and an opposing force, such as set forward. In the new device, the gate element is normally locked in its safe position by means of a pin slidable in the gate under the force of setback when the projectile is fired, the pin being secured against movement from its locking position, preferably by means of a spring. In one form of the device, the spring is in the form of a collar on the locking pin, and when the device is subjected to a force of setback, the collar is displaced from the pin so that the latter is movable by a force set forward to a position In another form of the invention, the spring normally maintains the locking pin in its operative position and is distorted to accommodate movement of the pin to an inoperative position by explosion of a detonating cap which is fired by the force of setback of the pin. When the pin releases the gate, the action of centrifugal force on the gate moves it outwardly to unblock the ring train.

Another object of the invention is to provide a noval safety gate in which the gate element remains in its safe or unarmed position despite rough treatment, such as dropping or tumbling the projectile.

These and other objects of the invention may be better understood by reference to the accompanying drawing, in which Fig. 1 is a side view of a projectile embodying one form of the new safety device, with part of the projectile casing broken away to show the device;

Fig. 2 is an enlarged transverse sectional view of the device shown in Fig. 1;

Fig. 3 is a sectional view of the line 3--3 in Fig. 2;

Fig. 4 is a view similar to Fig. 3 showing the position of the locking pin after it has been subjected to a force of setback;

Fig. 5 is a view similar to Fig. 4 showing the leerme :sie irraliste-retries subjected to' arme Dieet erward; and

tidinal "sectional view "of part oflftl'dvie, l

thef'nimeral III designates "e'i.` p" I taining an explosive liaige'ii -a'd'abbster-init I2 embedded in the charge. The booster is threaded into a recess I3 in the rear end of a body I4 which houses the parts of the safety device. At its front end, the body I4 is externally threaded, as shown at I4a, and is screwed into the rear end of a can I5 containing the parts of a fuze (not shown).

In the front end of the body I4 is a recess I6 for receiving a squib holder Il which may be secured in the recess in any desired manner. An axial port or bore I8 extends between the recess I 6 and the socket I3 for causing an explosion in the squib holder to detonate the booster I2. In the bottom of recess I6 is a central elongated slot I9 which is relatively shallow near the port I8 so as to define a shoulder 20, the slot I9 intersecting the port I8 to the rear of a squib 2l dis posed in a recess 2 Ia in the rear face of the holder Vi. An elongated gate element 22 is slidably mounted in the slot I9 and is provided on its rear face with a shoulder engageable with the shoulder 20 for limiting inward movement of the gate. When the gate is in its innermost position, as shown in Figs. 2, 3 and 4, it blocks the port I8 so as to prevent firing of the booster I2 by accidental explosion of the squib 2 I.

In order to lock the gate 22 in its innermost or safe position, I provide a detent pin 23 extending through an opening in the outer portion of the gate and projecting rearwardly into a socket 24 in the body I4. The-front end portion of pin 23 projects from the gate and has an annular groove for receiving a spring collar 25 normally seated on the front face of the gate, the collar and the front end of the pin being disposed in a recess 26 in the rear face of the squib holder I 1. A socket 21 in the holder I1 communicates with the recess 26 and is disposed in line with the front end of locking pin 23.

When the projectile is fired from a gun the force of setback moves pin 23 rearwardly into socket 24, thereby forcing the spring collar 25 oif the front end portion of the pin. The collars 25, when it is released from the pin, moves outwardly in recess 26 (Fig. 4) under the action of centrifugal force incident to rotation of the projectile. Thereafter, the force of set forward following deceleration of the projectile moves the pin 23 forwardly through the gate 22 into the socket 27 so as to release the gate. The gate 22 is then shifted outwardly in recess I9 by centrifugal force to clear the port i8, as shown in Fig. 5, whereby the squib 2l is adapted to explode the booster in recess I3 through the discharge port i8.

The modied construction shown in Fig. 6 is generally similar to that shown in Figs. 2 to 5, inclusive, except that the gate 22 is normally locked in its safe position by a pin 23a which is urged by a coil spring 29 against an explosive cap 311 disposed in the socket 24. The spring 29 is seated at one end in a recess in therpin 23a and at its opposite end on the bottom of socket 21. In the operation of this form of the device, the force oi' setback incident to ring the projectile from a gun causes the pin 23a to move rearwardly and explode the cap 30, whereupon the pin is moved forwardly against spring 29 into the socket 2l'. Accordingly, the gate 22 is released and moves outwardly in recess I9 under the action of centrifugal force to unblock the Squib dis charge passage I8. i

The new safety device provides an effective means for preventing premature detonation of a `projectile fuze. Since the pin 23 can move rearwardly into the socket 24 only when acted4 upon by a force of setback, it cannot be easily 4 dislodged by rough handling. Also, the gate 22 is finally released from its safe position only after the spring collar 25 has been removed by a force oi setback and the pin 23 has moved into socket 27 by a force of forward set.

I claim:

A safety device for projectiles, comprising a gate movable between operative and inoperative positions, a member normally locking the gate in its operative position, the member being movable in one direction in the gate by a force of p setback and in the opposite direction in the gate to release the gate, and an explosive device mounted at one end of said member and operable by a force of setback on the member to move the same in the direction for releasing the gate.

WILLIAM J. FLETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Nam-e Date 1,374,705 Wright Apr. l2, 1921 2,167,302 Junghans July 25, 1939 2,345,618 McCormick Apr. 4, 1945 

